A cold front is the leading edge of a cooler mass of air, replacing at ground level a warmer mass of air, which lies within a fairly sharp surface trough of low pressure.
Yes it is polluting the river with everything the manufaturing plant gives off such as the chemicals released in the air
And a water molecule, this is called a dehydration synthesis. when 2 molecule combine, a water molecule leave.
According to Arrhenius Theory of acids and bases, an Arrhenius base, when dissolving in water, produces the only negative ion: OH-.
Therefore, (3) OH- is the correct answer.
Hope this is helpful~
